import numpy as np
import pandas as pd
arr=np.random.randint(1,20,size=(3,3))
df=pd.DataFrame(arr,columns=['c','b','a'])
print('原始数据:\n',df)
print('按行索引降序排序：\n',df.sort_index(ascending=False))
print('按列标签升序排序：\n',df.sort_index(axis=1))